The present invention relates to a platen for use in an inkjet recording apparatus capable of performing a so-called marginless image recording, in which an image is printed on the entire area of a printing medium (for example, recording paper) without leaving a margin, and to an inkjet recording apparatus provided with the platen.
In a general inkjet recording apparatus, an ink ejection surface of a recording head mounted on a carriage, which is reciprocable in a main scanning direction, is provided so as to face a recording surface of a recording paper as a recording medium. A platen is provided to support the recording paper from under the recording paper such that a distance between the ink ejection surface and the recording surface of the recording paper is defined. Recording of an image is performed by ejecting ink from the ink ejection surface while the recording paper is supported by the platen.
There has been an inkjet recording apparatus, in which a so-called marginless image recording can be preformed by ejecting ink to an area larger than the recording surface of the recording paper and thereby recording an image over the entire surface of the recording paper without leaving a margin.
There is a known inkjet recording apparatus which comprises a platen including a slanting surface in a position facing a recordable area of a recording head, and an ink absorbing member arranged in the vicinity of a wall surface formed integrally with and in a lower portion of the slanting surface.
A plurality of ribs are formed on the slanting surface so as to extend in a recording paper conveying direction. The ribs are also arranged in predetermined intervals in a direction perpendicular to the recording paper conveying direction. Each rib includes an absent part, through which ink discarded during marginless image recording is discharged. The discarded ink then flows on the slanting surface and is absorbed by the ink absorbing member. It is advantageous to provide a groove in the slanting surface and the wall surface for accelerating the flow of discarded ink, the groove extending downward along the slanting direction or along the wall surface.
Also, there is a known waste tray for collecting ink discarded in an inkjet recording apparatus. The waste tray comprises a non-collecting area, an ink receiving area and a collecting area. A first ink absorbing member is provided in the ink receiving area, while a second ink absorbing member is provided in the collecting area. A plurality of V-shaped grooves as “ink guide passages” are formed in a bottom portion of the non-collecting area in predetermined intervals. Ink discarded into the non-collecting area flows in the V-shaped grooves, and thereby is rapidly discharged into the ink receiving area communicating with the non-collecting area.
As described above, it is common to provide grooves as “ink guide passages” in a path of ink (e.g., a horizontal surface, a slanting surface or a vertical surface) in order to rapidly and smoothly guiding discarded ink to the ink absorbing member.
However, the platen and the ink absorbing member in the known inkjet recording apparatus involves a disadvantage. Specifically, even when discarded ink rapidly flows through the grooves formed in the slanting surface and the wall surface, the ink flowing from the slanting surface to the wall surface will collectively flow into a portion of the ink absorbing member adjoining the slanting surface. Accordingly, the ink can be absorbed only through a limited portion of the ink absorbing member.
In the above described waste tray, in which grooves are provided only in the path of ink for guiding discarded ink to the ink absorbing member. Since the ink will collectively flow into a limited portion of the ink absorbing member in communication with the path of ink, the ink can be absorbed only through the limited portion of the ink absorbing member.
Accordingly, known technologies described above involve a problem that discarded ink cannot be absorbed rapidly by the ink absorbing member since the ink is absorbed only through a limited portion of the ink absorbing member adjoining an end portion of the slanting surface or the path of ink through which the ink flows.
The fact that ink is absorbed only through a limited portion of the ink absorbing member leads to a further problem. Specifically, since an ink absorption amount in the limited portion will easily reach saturation and the limited portion will easily lose absorbing ability due to aging deterioration caused by the ink absorbed by the limited portion, the ink absorbing member may become unable to absorb discarded ink, despite that the remaining portion of the ink absorbing member still has a sufficient ink absorbing ability.
There is another known inkjet recording apparatus which comprises a platen including a groove for discarding ink therein and an ink absorbing member, which is made of an elastic absorbing member and is contained in the groove, to perform marginless image recording. Discarded ink resulting from recording without leaving a margin on an edge portion of a sheet of recording paper is absorbed by the ink absorbing member contained in the groove provided in the platen. Accordingly, the discarded ink will not attach the sheet of the recording paper or the next sheet of the recording paper. Thus, soiling of the recording paper can be prevented.
However, the another known inkjet recording apparatus involves the following disadvantage. Specifically, when a user opens a cover of the inkjet recording apparatus the ink absorbing member, which is contained in the groove provided in an upper surface of the platen, is exposed. Then, a hand of the user during an operation is likely to directly touch the ink absorbing member becoming dirty as time passes and thereby to get dirty.
Also, the ink absorbing member must be arranged so as not to project above an upper end of a rib formed on a surface of the platen to prevent an upper surface of the ink absorbing member from contacting a reverse surface (a surface which is not a recording surface) of the sheet of the recording paper conveyed. It is, therefore, necessary to strictly regulate the dimensions and the shape of the ink absorbing member and arrange the same on the platen. A material having a low shape stability, such as an elastic absorbing member used for the ink absorbing member, requires time and labor both in regulating the dimensions and the shape and in installing the ink absorbing member in the platen.
Furthermore, if the ink absorbing member becomes fuzzy, it is likely that fuzzy fibers soaked with ink will project from the groove in the platen and thereby will contact and soil the reverse surface of the sheet of the recording paper.
In addition, when a user opens the cover of the inkjet recording apparatus, the ink absorbing member, which is contained in the groove of the platen and becomes dirty as time passes, is seen by the user. The user who should insert his/her hand into the inkjet recording apparatus for some operation may feel uncomfortable to see noticeable dirty ink spots of the ink absorbing member. To avoid causing such an uncomfortable feeling, it is necessary to employ a material in black or dark gray for the ink absorbing member. This will result in a limited selection of a material for the ink absorbing member, and thus limiting the possibility of apparatus design.